A perennial topic. The organisms we see cluster around specific, distinct types. We can identify an individual as belonging to that type because it has the distinctive characteristics of that type. We know what the characteristics are because we see a lot of such individuals.
To the some Creationists, those types represent essential, immutable forms, perhaps with some post-Ark latitude, and a bit of variation around the ‘norm’. It is as if those forms were cast from a mould, with small manufacturing defects. The mould is eternal, unchanging.
To the Evolutionist, those types are simply the current form of a changing lineage. Lineages can branch and diverge leading to an increase in the total numbers, offset by extinction. The branching process is somewhat extended in time, so species are not only malleable but somewhat blurry around the inception of a bifurcation. Intraspecific variation does not become interspecific variation overnight.
The Creationist demands to know how one type can ‘become’ another – how one unchanging essence can become another unchanging essence. The Evolutionist answers that their conception of ‘species’ is awry – one type becomes another, or two, gradually, changing like minimalist music. The type ‘floats on the breath of the population’, as Dr Johnson said of the unwritten Erse language. The Creationist responds that this is begging the question – defining species in evolutionary terms is an attempt to prove evolution by definition.
Nonetheless, if you are talking of evolution, your species concept needs to take account of it. An essentialist conception is no use in an evolutionary framework. There is, in my opinion, no non-arbitrary means of distinguishing species from other taxonomic ranks while interbreeding (and hence gene flow) is possible. This is the limit of the Biological Species Concept – a biospecies is the set of all the individuals which can create viable fertile offspring with at least one other member of the set. This can frequently be far too broad – maples separated for 20 million years can interbreed, and fertile hybrids between morphologically distinct types, even those assigned to different genera, are common. It is also difficult practically to assess whether the sets are ‘really’ separate yet. At the extreme, a single introgression among billions of incompatible pairings would indicate incomplete speciation, to a BSC pedant.
Creationists claim an objective means (as they do in other arenas …) but take them out in the field and I suspect their hypothetical methodology would fail them. If we base it on ‘morphology’, just how does one rank characters objectively? A wing-bar, beak colour, gregarious, particular mating dance, blue eggs, prefers shrimps … how many characters, which ones are more important, and by how much?
I would take as an example the Spotted sandpiper and Common sandpiper. These are held to be an example of parapatric speciation – they occupy different but contacting ranges, and within those ranges, for reasons unknown, gene flow in a single ancestral species between the ranges gradually diminished. Potential causes include a temporary ‘firebreak’ where no individuals penetrated, dichotomous mate preference, or ecological specialisation. Now, again for reasons not entirely obvious, they do not penetrate each others’ ranges except in narrow contact zones. At these zones, hybrids frequently occur. So on the BSC, speciation is not complete (indeed, the Common also interbreeds with sandpipers of a different genus, so on the BSC they join in too). But they are clear morphological species. Are they Platonic? Were they both on the Ark?
ALL of the scientific Creationists say what I did. All of the Creation orgs agree with me.
So evolution is “stuff happens.” I knew that.
Care to explain how evolution can be both cause and effect? If people don’t even know whether evolution is cause or evolution is effect then they don’t know what evolution is.
When you quote yourself….
I believe that the whole reason for discussing “species” here was that people felt that to know whether experiments like Lenski’s had addressed “macroevolution” one needed to know whether a new species had been achieved.
I wonder whether that is a sensible approach to the issue. After all, it is creationists who make a big distinction between “macroevolution” and “microevolution”. And when they are pressed on it, they do not use the species level to decide which phenomenon they are discussing. Instead they start talking about the origin of new major body plans, which is not necessarily happening when a new species arises.
So it may well be that in discussing what happens when you go from one species to many, they will end up saying that this is merely microevolution.
Your prescience is uncanny, Joe! Vincent Torley chimes in..
If we adopted platonic essentialism tomorrow we would not put taxonomists out of business the hard and messy work of actually categorizing organisms would continue. What would change is we would have confidence that our work in this regard is not in vain. There is something ontologically real behind our intuitions that organisms can be divided into species.
I don’t think you are understanding what I’m suggesting.
I’m suggesting that we look at phenotype when we categorize organisms. The genotype would be beside the point in taxonomy if I was in charge. What matters to me when looking at species is what an organism is not how it got to be that way.
It would not matter how close or how far the genotypes of ‘Zobras’ and ‘Yoks’ were. What would matter is the characteristics of the organisms in question
peace
Well lets see if I can stir it up some more.
When archaic homo sapiens acquired language speciation occurred. This change may or may not be reflected in the genome.
I have a full time job and it’s not in biology. I made an offhand remark on an obscure website in response to a direct question from you. I think an approach similar to the one I laid out would be fruitful but I have neither the resourses nor the inclination to pursue it.
If biologists are happy with the current paradigm more power to them. They should just understand that their pursuits will continue to seem pedantic and the species problem will not go away.
peace
LoL! Macroevolution is more than just mere speciation. Creationists accept speciation.
While I have a minute. I’d like to show the relationship between this conversation and the idea behind my tool
Look at the following numerical sequences
314159265359
315158265349
The first sequence is the first 12 digits of Pi the second is not.
This is an objective fact. It does not matter that the two strings are close and it does not matter that the second string was produced by mutating 3 digits in the first string
What matters is the information encoded by the string and not the numbers themselves. The Phenotype not the genotype
An interesting side note is that once you know the “form” the first string represents you will always be able to distinguish it from other strings even strings that are close.
peace
The second string will, of course, exists somewhere in the expansion of pi.
Correct but it will never ever be the first twelve digits of Pi. You can expand the first string the second not so much. That is the difference between the two.
peace
Perhaps you’d care to demonstrate how you obtain those digits.
What do they say is the mechanism behind these changing kinds?
Frankie,
Bollocks. Scientific creationists? No such thing.
Joe Felsenstein,
Not entirely. Discussion of species/speciation was clogging the Mendel’s Accountant thread, so I moved it here for a general discussion of whatever people think ‘species’ means. I don’t think Lenski’s bugs are worth a new name, FWIW, but it is an opportunity to thrash out the terminology.
fifthmonarchyman,
What, ignore the heritable material? That would be stoopid, when it is sitting right there and we know what its sequence is, and its relevance to descent. Why would we do this, other than to close both our eyes to biological reality, which includes genetics?
Well, my point has evidently gone whizzing over your head.
fifthmonarchyman,
Your method does not make the species problem go away. It simply applies to a fiction – a world of compartmentalised biology which exists only in your head.
‘Frankie’ might like to tell fifthmonarchyman that ‘scientific Creationists’ accept speciation and extremely rapid evolution, and that Platonic essentialism is no longer accepted by people who realise, at the very least, you can’t get 8.7 million species on a small boat. .
And he might like to tell everyone else how ‘scientific Creationism’ identifies Commonly Descended clades and distinguishes their Created origin.
Eat me- there are plenty of scientific creationists. There are plenty of creationists who are scientists.
And all you have to do is look at Answers in Genesis- ICR- pick one. They all agree with me.
All he has to do is read Answers in Genesis or the ICR. And all Allan has to do is google “baraminology” and I am sure he could find the information he is looking for.
Genetic variation. Some accidental- the diseases and deformities. And others directed as in “built-in responses to environmental cues” Spetner 97
Hi Joe! When did TSZ reinstate you for the suspension for posting porn?
I would hope that folks know that I’m not YEC and that my opinions are only my own.
My YEC friends think I’m a sell out because I don’t think the Bible says the flood was global or that the world is young.
lots of my ID friends think I’m a sell out because think that all all the features present in life could have been front loaded in the first cell or the environment so that life could unfold with out any special divine intervention.
My Darwinist friends think I’m a ignorant buffoon because I think that some things in the universe are best explained as being the result of an intelligent cause .
That pretty much puts me on an island all by myself. I don’t mind this arrangement at all it’s fun playing the gadfly .
peace
The first sequence was frontloaded the second one was obtained by randomly mutating some digits in the first one. Like I said when it comes to essentialism it does not matter how the digits got here it only matters what they do.
peace
Interesting. So you think there wasn’t any real evolution?
Perhaps right after they allowed you to get away with the following:
A claim you never substantiated with any evidence whatsoever.
Ah yes. Yet another in the long list of “skeptical” myths.
For the same reason we ignore the caloric content of the specimen or it’s speed of decomposition because we are trying to understand the “form” of the organism and stuff like that is irrelevant to this quest.
Genetics is important to biology it’s not that important to the “form”
peace
Stupid stupid thing to say.
You have no idea what you’re talking about. I wager you’ve never used a key to spec out different species. I’ll take a small side bet that you don’t even know what a “key” is, in this context, without looking it up.
This group always has orange blotches. That one never does. Okay, looks clear enough to call them separate species. But wait a minute, those ones over there have a red blotch. Does that mean they’re a separate species, too? Lump those in with only-orange-blotch species? Or does it mean that blotchiness/lack of blotchiness is actually unimportant for determining which species, just as freckles/no freckles is totally unimportant for determining whether you’re a member of the human species?
The reason why scientists are so thrilled to have genetic tools to help determine divides between similar species is because the visible characteristics of the organism often cannot be agreed upon in our fuzzy, continuous, non-sharp boundary world.
Because you’re a god-besotted medievalist thinker, you believe dear old Linnaeus should still be good enough. Well, that plus special revelation from god for the really hard cases. But it’s really not good enough, and if Linnaeus could be here today, he would be the first to say bring on genetic identification.
Fortunately, real science doesn’t listen to the goddy fools.
Hey, maybe you could start a more productive campaign instead: bring back black-and-white movies!
You’re wrong. As usual. We did not have a speciation event when we “acquired” language.
Even you can’t be that ignorant. Or maybe you’re high on something. Or not. Which leaves trolling as an explanation for your comment — and note that you did want to “stir it up”.
As my friends say, “Go home, Tardis. You’re drunk.”
I wouldn’t be so gleeful about that if I were you.
Mung, your “I’m a CHRISTIAN and better than you!” anti-gay ranting at UD isn’t exactly a secret.
Are you saying you’ve reversed your position and now fully support same-sex marriage, equal rights for all LGBT people, and fines/jail for bigots who violate anti-discrimination laws against gays?
Adapa, best moved to Noyau — or perhaps start a new thread on gay rights. Last one was a doozy. 🙂
Colour of skin is a important biological adaptation. It is important to tigers and lions in making a case they are different species. However differences between people are more then mere colour. There are real anatomical differences that would justify them as species in the same rules for lions/tigers.
species is a invention unrelated to actual biological processes and so results.
In fact evolutionism etc could only claim there are species IF it was essential to evolving new populations that can avoid extinction by breeding with cousins and allow more variation in the population to create more biological difference and so , if reproductively inoperative, new species.
Does evolutionism need species to hold and advance evolution?
Otherwise species is unrelated to biology.
There is just change in populations bringing new body types relative to the parent type. How different, and so breeding walls, is irrelevant to the mechanism for the new population.
For both creationists and evolutionists.
its funny species has not been coined as a myth.
Unless its demanded its needed.
Frankie,
I am not saying there are NO Creationists who accept some speciation. But clearly, particularly among the ‘ordinary Joe’ kind of Creationist, there are many who adopt the immutabilist position. My remarks about species-immutabilism were directed at them, including the individual who prompted these side-discussions (eta: who is now claiming not to be an immutabilist, despite arguing for Platonism).
People who believe in ultra-rapid ‘kind’ evolution have different problems to deal with. And to be considered ‘scientific’ Creationists, they need to actually – you know – apply some science to the matter. Most of the sciency stuff – Axe, Gauger, Sanford – is actually attempting to tell us that evolution is impossible, so there’s a bit of an anomaly there.
Frankie,
Translation: “I got nothin’.”
Mung,
How do you work that out? ‘Real evolution’ is not limited to the arena where sufficient change has accumulated to force humans to rename the organism.
A->A’->A”->A”’->B
Each step is evolution. You think it’s only applicable to A->(…)B ?
Mung,
This in a post shortly following one where you appear to adopt that very position – “Lenski is not really evolution because we did not rename?”.
fifthmonarchyman,
That is ridiculous.
fifthmonarchyman,
There is a fine line between being a gadfly and trolling.
fmm has been arguing for Platonic essence, but now announces that the whole thing could have equally been front-loaded in one cell. The diametric opposition of those two positions can only be sustained in the head of someone who thinks that genetics is not relevant to either ‘form’ or taxonomic relationship. I’ll argue for any position that takes my fancy, ‘cos I’m a gadfly! Bzzz bzzz.
Which isn’t a problem, as long as people are clear, when they use the word, or it’s clear by the context, what they mean.
Lots of words in English have multiple, similar, meanings. That’s only a problem if people aren’t clear which meaning they intend at any given time.
Sure.
The word “evolution” (in the Darwinian sense, I’m not talking about usages like “the evolution of Shakespeare’s plays”) can refer to a postulated process, namely the process by which heritable variance in reproductive success in a given environment results in the population acquiring adaptations to that environment – big ears, for instance in a hot climate, or thicker fur in a cold one.
In that sense it is a cause – “evolution” as in “Darwin’s proposed evolutionary process” caused population A to adapt to a hotter/colder climate.
It can also be used to refer to the results of this process, as in “the evolution of the desert/arctic fox”. A better term, perhaps, would be “the adaptive evolution of the desert/arctic fox”, which would have the additional advantage of distinguishing adaptive evolution from simple change in a population over time, which need not be adaptive.
So yes, it is confusing – but not impossible to follow. There is no confusion in the theory (well, sometimes a little, but that is the case with the um evolution of all scientific models), just some confusion in the terms used.
Personally, I like to reserve the word “evolution” for “changes in a population over time”, regardless of whether the changes are adaptive or not, and “adaptive” evolution” or “biased reproduction” for the Darwinian kind (where there is adaptive change owing to some variants having better chances of successful reproduction in the current environment than others) and “drift” or “unbiased reproduction” for evolution that results simply from “drunkard’s walk” changes in variant frequencies where there is nothing about the variants themselves that makes them more or less likely to reproduce successfully.
And “speciation” for the bifurcation of lineages in which two branches become progressively less likely to interbreed. This can be triggered by simple geography, or more complex interactive positive-feed-back processes.
One thing worth saying maybe is the “speciation” doesn’t mean, and never has meant, some non-gradual major genetic jump between one generation and the next.
Such jumps may occasionally have occurred, and they may have resulted in speciation (in the bifurcation sense) but speciation does not require such a jump, nor does such a jump necessarily result in speciation.
Mung,
A mendaciously stupid rewording of what I wrote.
This is a dumb game. You, Joe, phoodoo – you all try this ridiculous “no-one knows what evolution is” gambit. I just told you what it is, and all I got back was uncomprehending blinking. It isn’t ‘stuff’, it is heritable change in population and lineage. There are numerous well-established causes of that change, and I’m virtually certain you will have encountered them all in your lengthy internet career. So don’t play dumb.
So what you are saying is this: You are wrong, and I am right. However you’ll just have to accept that as I’m not willing to put the effort in to demonstrate the truth of that claim.
And it also demonstrates how little you understand of the shared scientific enterprise. If you really had a better way of classifying biology all you would have to do is write a short paper with a couple of examples and explain how that work could be continued by others. Other people, keen to make their name in the world of science, would jump on any such improved system and progress it on your behalf. That’s how it works!
So, once again, under your improved scheme how many species of bacteria are there? One? More then one?
Those keen young researchers won’t be able to create the better classification system you know exists unless you drop a few hints now and again…
Though polyploidy in plants can result in speciation in a single generation. I sometimes think examples from plant speciation tend to be neglected.
I came across this article by Allan MacNiell which doesn’t neglect plant biology.
Clearly, we do need a species concept that covers generational change, if only to accommodate fossils. Speciation may be restricted to bifurcations, but sufficient-change-to-categorise occurs vertically too on many scales. The total change is split between two lineages in the parallel case.
Mung,
Would study of a social ‘revolution’ be a study of cause or effect? How ’bout gravity? Like I say, the only one who seems to be struggling with the concept is you. Try harder.